1. Field of the Invention:
The present invention relates to snap-fit or quick connectors, and more particularly to such connectors which are employed in fluid conduit systems to facilitate assembly and disassembly.
2. Description of the Art:
Snap-fit or quick connectors have been found to be useful in a wide range of applications. In particular, they are frequently employed for joining fluid carrying conduits in automotive and industrial applications. Such connectors have found general acceptance as they are typically capable of being closed in a single uniaxial movement which facilitates automated assembly, and entail simple designs which are relatively inexpensive to produce.
A further advantage of quick connect fittings is that they provide an effective seal for handling volatile or hazardous fluids, such as gasoline, while permitting ease of disassembly and reassembly during repair of a host system. Although tools are often required to effect release of quick connect fittings, designs such as those described in U.S. Pat. Nos. 3,990,727, 4,844,512 and 4,991,882 provide for manual release of the fitting without the necessity of separate tools. Although representing an advancement in the art, such "squeeze-to-release" designs often have certain shortcomings.
In applications where hazardous material is to flow through a fitting, prevention of inadvertent release is of primary concern. Accordingly, relatively high axial pull-apart strength specifications are mandated. In order to comply with such specifications, manufacture's of prior art designs typically employed material with a relatively high characteristic flex modulus (such as glass filled Nylon 12) to prevent warping or deformation of abutting locking surfaces within the connector under axial loading conditions. Unfortunately, materials with increased flex modulus are inherently stiffer and can require substantially higher release forces. A related problem is found in that the stiffer material tolerates only relatively short radial displacement of the female connector abutment surface to effect release. This provides relatively little "purchase" (or degree of radial overlap) of the mating abutment surfaces in the engaged condition, thereby exacerbating potential pull apart problems.
Lastly, known prior art designs were prone to fatigue leading to failure after a relatively small number of engagement-disengagement cycles.
The squeeze-to-release quick connector shown in U.S. Pat. No. 5,213,376, assigned to the assignee of the present invention, was designed to overcome these shortcomings. This connector has a pair of parallel arranged beam members, each affixed at one end to a retaining ring and at the other end to a mount located on the outside surface of the body portion of a female connector member. Two or more spaced detents extend inwardly from the retaining ring to capture an abutment surface of a male connector member to effect positive axial engagement between the female and male members. The beam members preferably extend axially a distance approximately equal to the characteristic inner diameter of the body portion of the female member.
While the connector shown in U.S. Pat. No. 5,213,376 provides positive axial engagement and quick and easy squeeze release of the two connector members, it would be desirable to further improve this connector to provide greater flexure for an easier squeeze release with less force; while still retaining positive axial engagement between the two connector members and a high pulloff strength when the connector members are in their connected state.
To meet these objectives, a squeeze-to-release quick connector was developed for the assignee of the subject invention as shown in FIG. 1. This quick connector 10 includes a female connector part 12 having an elongated body with an internal stepped bore extending inward from one end which communicates with a generally cylindrical bore extending to an open second end. A top hat or bushing 14 is fixedly mounted in an undercut 16 formed in the stepped bore. An O-ring seal 18 is also mounted in the stepped bore axially in line with one end of the top hat 14. An annular retaining ring 20 is integrally formed with the female connector 12 and is axially spaced rightwardly, as viewed in FIG. 1, from the open first end of the female connector 12. The retaining ring 20 is joined to the remainder of the female connector 12 by two circumferentially opposed, generally parallel, axially elongated beam members 22 and 24.
The retaining ring 20 has a central opening 26 having a characteristic diameter to provide clearance for the insertion of a male connector part 28 through the retaining ring 20 and into the stepped bore of the female connector part 12. Two circumferentially spaced detents 30 extend radially inward from the retaining ring 20. Each detent 30 is angularly aligned with one of the beam members 22 and 24 and forms a radially tapering ramp surface on a side facing away from the central opening in the retaining ring 20 and a radially transverse abutment surface 32 on a side facing the open first end of the female connector part 12. A finger 34 extends axially from the abutment surface 32 on each detent 30 toward the open first end of the open female connector part 12.
The retaining ring 20 has a profile formed of upper and lower crescent portions joined at the ends thereof through web members to form a generally oval shaped profile.
The portions of the retaining ring 20 adjacent to beam members 22 and 24 are relatively stiff while the web members are relatively compliant. This enables the connector assembly 10 to be released to enable uniaxial separation of the female connector part 12 and the male connector part 28 by grasping and squeezing together grip surfaces formed on the web members. This squeezing action causes the web members to move from their normal position in which each detent 30 engages an enlarged annular flange 36 on the male connector part 28 to a release position in which the detents 30 are momentarily radially displaced outwardly to enable release of the male connector part 28 from the female connector part 12.
While this squeeze-to-release quick connector design has been found to exhibit high pull off forces, and relatively low insertion forces, it would still be desirable to improve on this design to provide a squeeze-to-release quick connector which has higher pull off forces and lower insertion forces. It would also be desirable to provide a squeeze-to-release quick connector which is usable with a standard male connector part or end form having a standard 8.75 mil. SAE standard diameter. It would also be desirable to provide a squeeze-to-release connector which is easy to squeeze to the release position and, even through repeated usage, does not exhibit a deterioration in connector pull out forces.